Clashes have erupted in Turkey after the death of a 15-year-old boy who has become a symbol of the protests that gripped the country last year.

Berkin Elvan, then 14, was on his way to buy bread in Istanbul when he got caught up in street battles between police and protesters on June 16.

He was hit in the head by a tear gas canister fired by police.

He slipped into a coma and became a rallying point for government opponents, who held regular vigils at the hospital where he lay in intensive care.

He died early on Tuesday morning, sparking clashes at the hospital, which police dispersed with pepper spray.

The death has also ignited new demonstrations across Turkey, another pre-election headache for prime minister Tayyip Erdogan, already battling a graft scandal which has become one of the biggest challenges of his decade in power.

Overnight police fired water cannon and tear gas in Ankara's central Kizilay square to scatter several thousand protesters who chanted: "Government of Erdogan, government of corruption, resign resign".

The police pursued the protesters into side-streets, where small clashes continued.

There was similar police intervention against thousands of protesters in Istanbul's central Istiklal street.

In the southern city of Adana, protesters threw stones and aimed fireworks at police lines as water cannon vehicles advanced against them, spraying water.

Large numbers also protested in the western cities of Izmir and Eskisehir in the most extensive protests since last summer's unrest.

Residents in some Istanbul districts banged pots and pans with spoons from the windows of their apartment blocks, reviving a form of protest popular last year.

Crowds chanted "murderer Erdogan" and "the murderer state will be brought to account" as mourners carried Elvan's coffin, wrapped in red cloth and strewn with red carnations, to a "cemevi", an Alevi place of worship, in central Istanbul.

Boy's mother cries at open window

Alevis are a religious minority in mainly Sunni Muslim Turkey, where their liberal version of Islam has often been at odds with Mr Erdogan's Islamist-rooted government.

Among the throng of up to 1,000 people, some waved plain red flags, while shopkeepers in the Okmeydani district pulled down their shutters as a mark of respect.

Elvan's mother, flanked by a group of women, stood crying at an open window.

"We have come here because of the murderer police. They will be held to account. Berkin Elvan's blood will not be left on the ground," said Ahmet Ekinci, one of those in the crowd.

Elvan, who will be buried today, was the sixth person to die in violence during nationwide protests in late May and June over Mr Erdogan's plans to bulldoze an Istanbul park.

The protests turned into one of the biggest shows of public defiance of Mr Erdogan's 11-year rule.

Mr Erdogan has cast the corruption investigation as a plot to unseat him by US-based Islamic cleric Fethullah Gulen, a former ally whose followers say they number in the millions and who wields covert influence in the police and judiciary.

Leaked voice recordings, many of them purportedly of Mr Erdogan, have appeared on YouTube over the past two weeks, part of what the prime minister sees as a campaign to sully his centre-right AK Party ahead of local elections on March 30 and a presidential race five months later.

Mr Erdogan has condemned the illegal tapping by Mr Gulen's followers of what should have been encrypted telephone conversations and has described some of the leaked recordings as "fabricated montage".